Nucleocrinus elegans (fossil blastoids) in fossiliferous calcareous shale (Silica Formation, Middle Devonian; quarry near Paulding, Ohio, USA) : 無料・フリー素材/写真
Nucleocrinus elegans (fossil blastoids) in fossiliferous calcareous shale (Silica Formation, Middle Devonian; quarry near Paulding, Ohio, USA) / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Nucleocrinus elegans Conrad, 1842 - fossil blastoids in fossiliferous calcareous shale from the Devonian of Ohio, USA.Blastoids are an extinct group of echinoderms. They resemble crinoids in having a head, or theca, perched atop a long stem of stacked columnals composed of calcite. Crinoids and blastoids are pelmatozoans - stalked echinoderms. Both groups are sessile, benthic, filter-feeding organisms. The overall structure and morphology of crinoid heads and blastoid heads are quite different. Blastoid heads have pentaradial symmetry and somewhat resemble closed flower buds or nuts. They have 5 ambulacral grooves extending outward and downward from the summit of the theca. During life, many thin, delicate brachioles extended from the ambulacral grooves - these structures captured tiny particles of food from seawater as the blastoid engaged in filter feeding.Classification: Animalia, Echinodermata, Blastozoa, Blastoidea, Spiraculata, NucleocrinidaeStratigraphy: Silica Formation, Middle DevonianLocality: quarry near Paulding, northwestern Ohio, USA-----------More info. at:en.wikipedia.org/wiki/Blastoid |
| 撮影日 | 2015-04-12 09:59:55 |
| 撮影者 | James St. John |
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